An experimental investigation of corrosion of X100 pipeline steel under uniaxial elastic stress in a near-neutral pH solution

Abstract

In this work, the effect of uniaxial elastic stress on corrosion of X100 pipeline steel in a near-neutral pH solution was investigated by localized electrochemical impedance spectroscopy (LEIS), corrosion potential and electrochemical impedance measurements, surface analysis techniques as well as finite element analysis. No effect of the static elastic stress on electrochemical corrosion potential of the steel is detected. The critical failure strain of corrosion scale formed on the steel surface is calculated to be 0.00357–0.00417, which is higher than the maximum strain of 0.0029 generated on the specimen. Thus, corrosion scale does not fracture during loading. No difference in the steady-state corrosion potential could be detected upon application of an elastic tensile or compressive stress. If the scale is pre-formed on the steel surface, the applied dynamic elastic load would “weaken” the scale by expanding its pores, and thus, increase the steel corrosion. While a dynamic tensile stress enhances the steel corrosion, the dynamic compressive stress would inhibit corrosion of the steel. This work provides important recommendations for pipeline safety design, where the corrosion enhancement due to the dynamic elastic stress should be considered.